/************************************************* * Luby-Rackoff Source File * * (C) 1999-2007 The Botan Project * *************************************************/ #include #include #include namespace Botan { /************************************************* * Luby-Rackoff Encryption * *************************************************/ void LubyRackoff::enc(const byte in[], byte out[]) const { const u32bit OUTPUT_LENGTH = hash->OUTPUT_LENGTH; SecureVector buffer(OUTPUT_LENGTH); hash->update(K1); hash->update(in, OUTPUT_LENGTH); hash->final(buffer); xor_buf(out + OUTPUT_LENGTH, in + OUTPUT_LENGTH, buffer, OUTPUT_LENGTH); hash->update(K2); hash->update(out + OUTPUT_LENGTH, OUTPUT_LENGTH); hash->final(buffer); xor_buf(out, in, buffer, OUTPUT_LENGTH); hash->update(K1); hash->update(out, OUTPUT_LENGTH); hash->final(buffer); xor_buf(out + OUTPUT_LENGTH, buffer, OUTPUT_LENGTH); hash->update(K2); hash->update(out + OUTPUT_LENGTH, OUTPUT_LENGTH); hash->final(buffer); xor_buf(out, buffer, OUTPUT_LENGTH); } /************************************************* * Luby-Rackoff Decryption * *************************************************/ void LubyRackoff::dec(const byte in[], byte out[]) const { const u32bit OUTPUT_LENGTH = hash->OUTPUT_LENGTH; SecureVector buffer(OUTPUT_LENGTH); hash->update(K2); hash->update(in + OUTPUT_LENGTH, OUTPUT_LENGTH); hash->final(buffer); xor_buf(out, in, buffer, OUTPUT_LENGTH); hash->update(K1); hash->update(out, OUTPUT_LENGTH); hash->final(buffer); xor_buf(out + OUTPUT_LENGTH, in + OUTPUT_LENGTH, buffer, OUTPUT_LENGTH); hash->update(K2); hash->update(out + OUTPUT_LENGTH, OUTPUT_LENGTH); hash->final(buffer); xor_buf(out, buffer, OUTPUT_LENGTH); hash->update(K1); hash->update(out, OUTPUT_LENGTH); hash->final(buffer); xor_buf(out + OUTPUT_LENGTH, buffer, OUTPUT_LENGTH); } /************************************************* * Luby-Rackoff Key Schedule * *************************************************/ void LubyRackoff::key(const byte key[], u32bit length) { K1.set(key, length / 2); K2.set(key + length / 2, length / 2); } /************************************************* * Clear memory of sensitive data * *************************************************/ void LubyRackoff::clear() throw() { K1.clear(); K2.clear(); hash->clear(); } /************************************************* * Return a clone of this object * *************************************************/ BlockCipher* LubyRackoff::clone() const { return new LubyRackoff(hash->name()); } /************************************************* * Return the name of this type * *************************************************/ std::string LubyRackoff::name() const { return "Luby-Rackoff(" + hash->name() + ")"; } /************************************************* * Luby-Rackoff Constructor * *************************************************/ LubyRackoff::LubyRackoff(const std::string& hash_name) : BlockCipher(2*output_length_of(hash_name), 2, 32, 2), hash(get_hash(hash_name)) { } }